Tractate Derekh Eretz Zuta

The characteristics of a scholar are that he is meek, humble, alert, filled [with a desire for learning], modest, beloved by all, humble to the members of his household and sin-fearing. He judges a man [fairly] according to his deeds, and says ‘I have no desire for all the things of this world because this world is not for me’. He sits and studies, soiling his cloak at the feet of the scholars. In him no one sees any evil. He questions according to the subject-matter and answers to the point.

Be like a gourd split open that the wind may enter, like a deep furrow which retains its water, like a jar coated with pitch which preserves its wine, and like a sponge which absorbs all. Be not like a wide opening which allows the wind to rush in, or like a narrow opening which injures the valuable [as they press through]. Be like a doorstep on which everyone treads and like a low peg which is within the reach of all.